According to a recently-released study that looked at if/how calorie posting at Starbucks affected total calorie consumption:
We find that mandatory calorie posting causes average calories per transaction to fall by
6% at Starbucks. The effect is long lasting. The effect is almost entirely related to changes in
consumers’ food choices—there is almost no change in purchases of beverage calories (Starbucks’
core business) [Food calories decreased by 14%, the study indicates elsewhere – Miesen]
The Discussion and Conclusion sections are really worth a read. The most shocking part of the whole study: a Venti White Chocolate Mocha has 580 calories – more than a KFC Double Down (which Nate Silver analyzes – statistically – here). I would not have guessed that.
The study also notes:
If we further assume that calorie consumption were reduced by 6% at all chain restaurants, and
that this reduction is not offset by increases at other meals, then it would imply a decrease in
total calorie consumption on the order of 1.5%. If average daily intake is around 2,000 calories,
the implied calorie reduction is 30 calories per day.
So, posting calorie counts seem to have an effect – but a negligible one, in the long run. Which begs the question: is it worth it? You can tell two different stories:
Yes, it’s worth it. A 14% reduction in food calories (on average) is a good start (and a “26% reduction for individuals that tended to make high-calorie purchases at Starbucks” is a better start). Consumers become more sensitive of what they’re putting in their bodies, which could lead to healthier eating decisions – which could lead to making healthier eating decisions outside of the restaurant (an effect this study can’t measure). If consumers are more aware, they may demand lower-calorie foods, which would lead restaurants/businesses to either a) offer more low-calorie foods; or b) reduce the calories in the foods they already do offer. It seems to me that the caloric content of many dishes at restaurants could be cut by 10% (either through smaller portion sizes or by using less butter/oil/cheese/etc.) with little discernible taste difference for the consumer. These are all good things.
No, it’s not worth it. As the study notes, “Three quarters of the reduction in food calories was due to consumers being less likely to purchase a food item, and one quarter of the effect was due to consumers
substituting towards lower calorie food items.” So 3/4 of the effect wouldn’t occur whenever someone goes to McDonald’s or Chipotle; they might choose a healthier option at that restaurant, but they’re still getting food. Also, anyone who really cares about counting calories probably already knows this sort of information; constantly seeing this information could actually make some people less happy. And, as the study noted, the effect is negligible on long-term weight-loss.
Ultimately, I’m inclined to believe that more information is better information, at least when it comes to caloric intake; if seeing the caloric content leads to smarter choices at the margin, then overall it’s a good thing. There won’t be one silver bullet for the obesity problem in America – many small decisions over a long period will be necessary. If I’m a little less happy knowing how many calories are in a White Chocolate Mocha, so be it.
P.S. For a must-read on obesity, read “Beating Obesity” by Marc Ambinder of the Atlantic – it might make you look at obesity differently.